In situ process for making quaternary ammonium bicarbonates and quaternary ammonium carbonates

ABSTRACT

Applicant has discovered an in situ method of preparing quaternary ammonium methocarbonate salts and quaternary ammonium alkylcarbonate salts in high yield from tertiary amines, methanol, and at least one of a cyclic carbonate, an aliphatic polyester (such as a polycarbonate), or an ester (such as a carbonate ester), and their subsequent conversion to quaternary ammonium bicarbonates, quaternary ammonium carbonates or both in a one-pot reaction. According to one embodiment of the invention, the method includes reacting an amine and methanol with at least one of a cyclic carbonate and an aliphatic polyester to yield a quaternary ammonium methocarbonate. This method does not produce or require the handling of corrosive quaternary ammonium hydroxides. Another embodiment is a method of preparing quaternary ammonium alkylcarbonate salts by reacting tertiary amines, methanol, and an ester. The quaternary ammonium methocarbonate or alkylcarbonate can be converted to the corresponding bicarbonate, carbonate, or mixture thereof by methods known in the art.

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/303,971, filed Jul. 9, 2001, which is herebyincorporated by reference.

FIELD OF THE INVENTION

[0002] This invention relates to an iii situ method of preparingquaternary ammonium alkylcarbonates (such as quaternary ammoniummethocarbonates), quaternary ammonium bicarbonates, and quaternaryammonium carbonates from corresponding tertiary amines.

BACKGROUND OF THE INVENTION

[0003] Quaternary ammonium compounds, such as didecyldimethyl ammoniumcarbonate and didecyldimethyl ammonium chloride, are known to haveantimicrobial activity. See, for example, U.S. Pat. Nos. 5,523,487,5,833,741, and 6,080,789. Quaternary ammonium compounds have been foundto be particularly useful as wood preservatives. However, quaternaryammonium chloride have been found to leach rapidly in soil (Nicholas etal., Forest Prod. J. 41:41 (1991)). Consequently, a metal coupler, suchas a copper salt, is frequently added to the quaternary ammoniumchlorides to prevent leaching.

[0004] Quaternary ammonium carbonates, on the other hand, have betterleaching resistance and do not require the use of a metal coupler. As aresult, there is an increasing demand in the preservative market forquaternary ammonium carbonates.

[0005] U.S. Pat. No. 5,438,034 discloses a process for preparingquaternary ammonium carbonates. The process includes reacting aquaternary ammonium chloride with a metal hydroxide to form a quaternaryammonium hydroxide and then reacting the quaternary ammonium hydroxidewith carbon dioxide to yield the quaternary ammonium carbonate. Thequaternary ammonium hydroxide, however, is very corrosive. In addition,metal chloride produced as a byproduct in the first reaction must befiltered out of the reaction product, a step which increases the costand decreases the efficiency of the process. Thus, an alternative methodto produce quaternary ammonium carbonates is desirable.

[0006] Werntz, U.S. Pat. No. 2,635,100, discloses a process forpreparing quaternary ammonium carbonates by reacting a trialiphaticamine with a dialiphatic hydrocarbon ester of carbonic acid, such asdimethyl carbonate and ethylene carbonate, preferably in the presence ofan alcohol. Werntz reported that the reaction of tertiary amines anddimethyl carbonate yielded quaternary ammonium methocarbonates. Werntzalso reported that when ethylene carbonate was reacted withtriethylamine and methanol, the cyclic carbonate oftriethyl-2-hydroxyethylammonium hydroxide was formed. The solvent,unreacted amine, and cyclic ester were removed by distillation. Manydialiphatic hydrocarbon esters of carbonic acid, such as dimethylcarbonate, are expensive and, therefore, significantly increase the costof preparing quaternary ammonium carbonates by this process.

[0007] Dimethyl carbonate is commercially available, and methods of itssynthesis are well known in the art. Typically cyclic carbonates, e.g.,ethylene and propylene carbonate, are converted to dimethyl carbonateand a glycol in the presence of methanol or other alcohol and catalyst.Romano et al., U.S. Pat. No. 4,062,884, disclose a process for preparingdialkylcarbonates by reacting an alcohol with a cyclic carbonate in thepresence of an organic base, such as a tertiary aliphatic amine. Romanoet al. describe the reaction of a methanol/ethylenecarbonate/triethylamine mixture. Continuous distillation of themethanol-dimethylcarbonate azeotrope over 3 hours resulted in almostcomplete conversion of ethylene carbonate to ethylene glycol anddimethyl carbonate. Romano et al. further teach that the organic basewhich catalyzes the reaction can be totally recovered from the reactionvessel by simple distillation.

[0008] There is a continuing need for cheaper and more efficient methodsfor preparing quaternary ammonium carbonates. A one step, in situ methodof preparing quaternary ammonium carbonates would advantageously meetthese needs.

SUMMARY OF THE INVENTION

[0009] Applicant has discovered an in situ method of preparingquaternary ammonium methocarbonate salts and quaternary ammoniumalkylcarbonate salts in high yield from tertiary amines, methanol, andat least one of a cyclic carbonate, an aliphatic polyester, and anester, and their subsequent conversion to quaternary ammoniumbicarbonates, quaternary ammonium carbonates or both in a one-potreaction. According to one embodiment of the invention, the methodincludes reacting an amine and methanol with at least one of a cycliccarbonate, an aliphatic polyester (such as a polycarbonate), or an ester(such as a carbonate ester) to yield a quaternary ammoniummethocarbonate. This method does not produce or require the handling ofcorrosive quaternary ammonium hydroxides. Furthermore, this methodadvantageously produces glycols as byproducts. Glycols are frequentlyadded to solutions containing quaternary ammonium carbonates andquaternary ammonium bicarbonates to raise their flashpoint and as ananti-freeze.

[0010] Another embodiment is a method of preparing quaternary ammoniumalkylcarbonate salts by reacting tertiary amines, methanol, and anester.

[0011] The present invention also provides a method of preparing aquaternary ammonium bicarbonate, quaternary ammonium carbonate, ormixture thereof by (a) preparing a quaternary ammonium methocarbonate ora quaternary ammonium alkylcarbonate by one of the aforementionedmethods, and (b) converting the quaternary ammonium methocarbonate orquaternary ammonium alkylcarbonate to the corresponding quaternaryammonium bicarbonate, quaternary ammonium carbonate, or mixture thereof.

DETAILED DESCRIPTION OF THE INVENTION

[0012] Applicant has discovered an in situ method of preparingquaternary ammonium methocarbonate and alkylcarbonate salts in highyield from tertiary amines, methanol, and at least one of a cycliccarbonate, an aliphatic polyester (such as a polycarbonate), and/or anester (such as a carbonate ester), and their subsequent conversion toquaternary ammonium bicarbonates, quaternary ammonium carbonates, ormixtures thereof in a one-pot reaction.

[0013] The term “alkyl” as used herein includes straight and branchedalkyl substituents. An “alkyl” group is a saturated hydrocarbon.

[0014] Preparation of the Quaternary Ammonium Methocarbonate

[0015] The method of the present invention can prepare quaternaryammonium methocarbonates having the formula

[0016] where R¹, R², and R³ are independently C₁-C₃₀ alkyl. Preferably,R¹, R², and R³ are independently C₁-C₂₀ alkyl and more preferably areindependently C₁-C₁₆ alkyl. Most preferably, R¹ is methyl.

[0017] Also, at least one of R¹, R², and R³ is preferably a C₈-C₃₀ alkylor a C₈-C₂₀ alkyl. According to one embodiment, R¹ and R² areindependently C₁-C₂₀ alkyl and more preferably are independently C₁-C₁₆alkyl and R³ is C₈-C₂₀ alkyl and more preferably C₈-C₁₆ alkyl.

[0018] According to a preferred embodiment, R² is C₁-C₂₀ alkyl.According to another embodiment, R² is methyl. According to yet anotherembodiment, R² is a C₈-C₁₂ alkyl and more preferably a C₁₀ alkyl.

[0019] According to a preferred embodiment, R³ is a C₈-C₁₂ alkyl andmore preferably a C₁₀ alkyl.

[0020] According to another preferred embodiment, R¹ is methyl and R²and R³ are independently C₈-C₂₀ alkyl. More preferably, R² and R³ areindependently C₈-C₁₂ alkyl. According to a more preferred embodiment, R²and R³ are C₁₀ alkyl.

[0021] According to yet another preferred embodiment, R¹ and R² aremethyl and R³ is a C₈-C₂₀ alkyl. According to one embodiment, R³ is aC₁₀-C₁₈ alkyl and more preferably is a C₁₂ or C₁₈ alkyl. According toanother embodiment, R³ is C₈-C₁₂ alkyl and more preferably is a C₁₀alkyl.

[0022] Representative quaternary ammonium methocarbonates include, butare not limited to, didecyldimethyl ammonium methocarbonate,dodecyltrimethyl ammonium methocarbonate, dioctyldimethyl ammoniummethocarbonate, octadecyltrimethyl ammonium methocarbonate,dioctadecyldimethyl ammonium methocarbonate, trioctylmethyl ammoniummethocarbonate, and any combination of any of the foregoing.

[0023] The quaternary ammonium methocarbonate is prepared by reacting anamine and methanol with at least one of a cyclic carbonate, an aliphaticpolyester (such as a polycarbonate), or an ester (such as a carbonateester). Suitable amines include, but are not limited to, those havingthe formula NR¹R²R³, wherein R¹, R², and R³ are defined as above.Preferred amines include, but are not limited to, didecylmethylamine,dodecylmethylamine, dioctylmethylamine, octadecyldimethylamine,dioctadecylmethylamine, trioctylamine, and any combination of any of theforegoing.

[0024] Suitable cyclic carbonates include, but are not limited to, thosehaving the formula

[0025] where R⁴ is hydrogen or C₁-C₄ alkyl and n is an integer from 1 to10. Preferably, R⁴ is hydrogen or methyl. Preferred cyclic carbonatesinclude, but are not limited to, ethylene carbonate, propylenecarbonate, and mixtures thereof.

[0026] Suitable aliphatic polyester include, but are not limited to,those having the formula

[0027] where R⁵, R⁶, R⁷, and R⁸ are independently hydrogen or C₁-C₁₀alkyl and m is an integer from 1 to 1200. According to one embodiment,R⁵, R⁶, R⁷, and R⁸ are independently hydrogen or C₁-C₄ alkyl.Preferably, R⁵, R⁶, R⁷, and R⁸ are independently hydrogen or methyl.According to a preferred embodiment, R⁵ is methyl and R⁶, R⁷, and R⁸ arehydrogen. Preferably, m ranges from 1 to 100.

[0028] Generally, the reaction is performed with a molar excess ofmethanol and cyclic carbonate, aliphatic polyester, or mixture thereofwith respect to amine, i.e., the molar ratios of methanol and the cycliccarbonate, aliphatic polyester, or mixture thereof to amine are greaterthan 1. The molar ratio of amine to cyclic carbonate, aliphaticpolyester, or mixture thereof preferably ranges from about 1:1 to about1:10 and more preferably ranges from about 1:1.1 to about 1:1.3. Themolar ratio of amine to methanol broadly ranges from about 1:2 to about1:20 and preferably ranges from about 1:3 to about 1:10.

[0029] The reaction is typically performed at from about 120 to about160° C., preferably from about 120 to about 150° C., and more preferablyfrom about 120 to about 140° C. The reaction may be performed at apressure ranging from about 60 to about 200 psi. Preferably, thereaction is performed at a pressure ranging from about 120 to about 150psi.

[0030] Generally, the reaction is performed for from about 3 to about 40hours and preferably from about 5 to 30 hours.

[0031] The reaction step yielding the quaternary ammonium methocarbonatealso produces glycols, such as ethylene glycol and propylene glycol, asbyproducts. For example, when the cyclic carbonate is propylenecarbonate, the reaction is as follows:

[0032] where R¹, R², and R³ are defined as above.

[0033] Without being bound by any theory, the inventor believes that thepropylene carbonate first reacts with methanol to form dimethylcarbonate and propylene glycol as shown below.

[0034] The amine NR¹R²R³ catalyzes this first reaction. The inventorfurther hypothesizes that the dimethyl carbonate formed reacts with theamine to yield the quaternary ammonium methocarbonate. Therefore, thereaction yields quaternary ammonium methocarbonate and propylene glycol.

[0035] Dimethyl carbonate may also be added to the reaction mixture toimprove the kinetics of the reaction, i.e., to accelerate the reaction.The dimethyl carbonate also functions to balance the ratio of quaternaryammonium bicarbonate and carbonate to glycol in the product. The molarratio of amine to dimethyl carbonate (before the reaction) preferablyranges from about 2:1 to about 1:3 and more preferably ranges from about1.25:1 to about 1:1.25.

[0036] The inventor has found that the molar ratio of total carbonatesources (i.e. total cyclic carbonate and aliphatic polyester) to aminein the reaction is preferably in the range of from about 1:1 to 5:1,more preferably 1.25:1 to 2.5:1, and most preferably 1:1.5 to 1:2.

[0037] Thus, the present reaction in a preferred embodiment uses a molarexcess of methanol and dimethyl carbonate relative to amine tosubstantially completely convert the amine to quaternary ammoniummethocarbonate. The cyclic carbonate is preferably substantiallycompletely converted to glycol and dimethyl carbonate. The glycol canremain in the product.

[0038] The molar ratio of cyclic carbonate to amine can be varied toobtain the desired weight ratio of glycol to quaternary ammoniummethocarbonate in the reaction product. While methanol in the finalproduct can be easily distilled off, removal of glycols is much morecostly. According to one embodiment, the molar ratio of cyclic carbonateto amine is slightly greater than 1, e.g., from about 1:1.1 to about1:1.5 or from about 1:1.1 to about 1:1.3. By keeping the molar rationear 1, the weight ratio of propylene glycol to quaternary ammoniummethocarbonate, such as didecyldimethyl ammonium methocarbonate, in thefinal product generally ranges from about 1:3 to about 1:7 and ispreferably about 1:5.

[0039] After the formation of the quaternary ammonium methocarbonate,excess methanol and dimethyl carbonate may be removed and recovered bysimple distillation. The quaternary ammonium, methocarbonate may beisolated and purified by methods known in the art.

[0040] Preparation of the Quaternary Ammonium Alkylcarbonate

[0041] According to another embodiment of the present invention,quaternary ammonium alkylcarbonates having the formula

[0042] where R¹, R², and R³ are defined as above and R⁹ is a C₁-C₁₀alkyl. According to one preferred embodiment, R⁹ is a C₁-C₄ alkyl. Morepreferably, R⁹ is methyl, ethyl, or propyl.

[0043] Representative quaternary ammonium alkylcarbonates include, butare not limited to, didecyldimethyl ammonium ethylcarbonate,dodecyltrimethyl ammonium ethylcarbonate, dioctyldimethyl ammoniumethylcarbonate, octadecyltrimethyl ammonium ethylcarbonate,dioctadecyldimethyl ammonium ethylcarbonate, trioctylmethyl ammoniumethylcarbonate, and any combination of any of the foregoing.

[0044] The quaternary ammonium alkylcarbonate is prepared by reacting anamine and methanol with an ester. Suitable amines include, but are notlimited to, those described above.

[0045] Suitable esters include, but are not limited to, those having theformula

[0046] wherein R⁹ is defined as above and R¹⁰ is a C₁-C₁₀ alkyl.According to one embodiment, R¹⁰ is a C₁-C₄ alkyl, such as methyl,ethyl, or propyl. A preferred ester is diethyl carbonate (i.e. where R⁹and R¹⁰ are ethyl)

[0047] Generally, the reaction is performed with a molar excess ofmethanol and ester with respect to amine, i.e., the molar ratios ofmethanol and ester to amine are greater than 1. The molar ratio of amineto ester preferably ranges from about 1:1 to about 1:10 and morepreferably ranges from about 1:1.1 to about 1:1.3. The molar ratio ofamine to methanol broadly ranges from about 1:2 to about 1:20 andpreferably ranges from about 1:3 to about 1:10.

[0048] The reaction conditions are generally the same as those describedfor the preparation of the methocarbonate.

[0049] The reaction step yielding the quaternary ammonium alkylcarbonatealso produces alkanols having the formula R⁹OH, R¹⁰OH, or mixturesthereof. For example, when the ester is cyclic carbonate is propylenecarbonate, the reaction is as follows:

[0050] where R¹, R², R³, R⁹, and R¹⁰ are defined as above.

[0051] Without being bound by any theory, the inventor believes that theester first reacts with methanol to form a methyl ester of the formulaCH₃OC(O)OR⁹, CH₃OC(O)OR¹⁰, or a mixture thereof and R⁹OH, R¹⁰OH, or amixture thereof. The amine NR¹R²R³ catalyzes this first reaction. Theinventor further hypothesizes that the methyl ester formed reacts withthe amine to yield the quaternary ammonium alkylcarbonate. Therefore,the reaction yields quaternary ammonium alkylcarbonate and alkanol(R⁹OH, R¹⁰OH, or a mixture thereof). The alkylcarbonate anion of thequaternary ammonium alkyl carbonate can be [OC(O)OR⁹]⁻, [OC(O)OR¹⁰]⁻, ora mixture thereof.

[0052] Alkyl methyl carbonate of the formula of the formula R⁹OC(O)OCH₃or R¹⁰OC(O)OCH₃ may also be added to the reaction mixture to improve thekinetics of the reaction, i.e., to accelerate the reaction. The molarratio of amine to alkyl methyl carbonate (before the reaction)preferably ranges from about 2:1 to about 1:3 and more preferably rangesfrom about 1.25:1 to about 1:1.25.

[0053] The inventor has found that the molar ratio of total carbonatesources (i.e. total ester) to amine in the reaction is preferably in therange of from about 1:1 to 5:1, more preferably 1.25:1 to 2.5:1, andmost preferably 1:1.5 to 1:2.

[0054] Thus, the present reaction in a preferred embodiment uses a molarexcess of methanol and alkyl methyl carbonate relative to amine tosubstantially completely convert the amine to quaternary ammoniumalkylcarbonate. The ester is substantially completely converted toalkanol and alkyl methyl carbonate. The alkanol remains in the product.

[0055] After the formation of the quaternary ammonium alkylcarbonate,excess methanol and alkyl methyl carbonate may be removed and recoveredby simple distillation. The quaternary ammonium alkylcarbonate may beisolated and purified by methods known in the art.

[0056] Conversion of the Quaternary Ammonium Methocarbonate orQuaternary Ammonium Alkylcarbonate to the Corresponding QuaternaryAmmonium Bicarbonate

[0057] The quaternary ammonium methocarbonate or alkylcarbonate producedby the method of the present invention can be converted to acorresponding bicarbonate, carbonate, or mixture thereof by methodsknown in the art, such as hydrolysis and other exchange reactions (e.g.,de-hydrolysis). For example, the methocarbonate or alkylcarbonate may bestirred with water at ambient conditions to effect the reaction(hydrolysis) to the corresponding bicarbonate and an alkanol (methanolin the case of the methocarbonate and R⁹OH, R¹⁰OH, or a mixture thereofin the case of the alkylcarbonate). Water may then be added to distillout the water and any residual methanol or methanol or other alkanolformed when the methocarbonate or alkylcarbonate hydrolyzes to thebicarbonate. The distillation may be done at atmospheric or reducedpressures by methods standard in the art.

[0058] The bicarbonate can be converted to the carbonate by any methodin the art. For instance, the bicarbonate can be heated (e.g. in water)to yield the corresponding carbonate, carbon dioxide, and water.

[0059] If methanol is distilled out of the bicarbonate solution, theheat may cause some or all of the bicarbonate to be converted to thecorresponding carbonate.

[0060] The methanol and alkanol in the product can be recovered by anymethod known in the art, such as distillation as discussed above, duringor after the reaction. The quaternary ammonium bicarbonate may beisolated and purified by methods known in the art.

[0061] The method of the present invention can produce quaternaryammonium bicarbonates having the formula

[0062] and quaternary ammonium carbonates having the formula

[0063] wherein R¹, R², and R³ are defined as above.

[0064] According to a preferred embodiment, the conversion results inthe formation of a mixture containing from about 70 to about 90% byweight of quaternary ammonium bicarbonate and from about 10 to about 30%by weight of quaternary ammonium carbonate, based upon 100% total weightof quaternary ammonium bicarbonate and quaternary ammonium carbonate.

[0065] Mixing, adding, and reacting steps in the present invention canbe accomplished by conventional means known to those of ordinary skillin the art. The order of addition of reactants or solvent in anyindividual step does not affect the process. Reactants and/or solventcan be added sequentially or simultaneously in any suitable reactionvessel. Importantly, the method of the present invention is suitable forcommercial scale production techniques and equipment, yet convenient forsmall scale work.

[0066] The following examples illustrate the invention withoutlimitation. All parts and percentages are given by weight unlessotherwise indicated.

[0067] A. Measurement of the Conversion of an Amine to the CorrespondingQuaternary Ammonium Methocarbonate

[0068] The amount of amine converted to the corresponding quaternaryammonium methocarbonate was determined as follows. Gas chromatographywas performed on a given sample after formation of the quaternaryammonium methocarbonate. Gas chromatography measurements of the solutionwere performed with a Hewlett Packard Model 5890 Series II chromatographequipped with a Hewlett Packard 7673 GC/SFC auto-injector which injects1 μl of solution into the injector at 300° C. The column temperaturestarts at 100° C. with a 5 minute hold followed by ramping at 8° C. perminute to 300° C., followed by another 5 minute hold.

[0069] In the gas chromatography injector, the quaternary ammoniummethocarbonate decomposes. For example, didecyldimethyl ammoniummethocarbonate decomposes to produce predominantly decene anddecyldimethylamine and small amounts of didecylmethylamine. In a puresolution of didecyldimethyl ammonium methocarbonate, thedidecylmethylamine peak contributes 13% of the areas of the totalchromatogram. The percentage of didecylmethylamine and propylenecarbonate converted to didecyldimethyl ammonium methocarbonate wascalculated by following the decrease in area for the didecylmethylaminepeak from 100% initially to 13% representing 100% conversion. The amountof other amines converted can be determined by similar methods.

[0070] A two phase titration with a standard sodium lauryl sulfatetitrant and bromophenol blue indicator was performed to confirm theformation of quaternary ammonium compounds.

[0071] B. Preparation of Quaternary Ammonium Methocarbonate

[0072] The following examples were performed in a 1 liter stainlesssteel Parr Model 4520 reactor equipped with a magnetic stirrer and aturbine type impeller. The temperature of the reactor was controlled towithin ±1° C. by a Parr Model 4843 controller with an electricalexternal heater and internal cooling by a water filled coil. An Ashcroftpressure gauge capable of measuring pressures ranging from 0 to 200 psiwas attached to the reactor. A small bleed valve was kept partially openuntil the contents of the reactor reached 60° C. to facilitate removalof residual air in the reactor.

EXAMPLE 1

[0073] The reactor was charged with 295 g (0.95 moles)didecylmethylamine (92% (w/w) pure and 8% (w/w) tridecylamine), 153 g(1.5 moles) propylene carbonate, and 177 g (5.7 moles) of methanol. Themixture was heated to 140° C. with stirring for 28 hours.Didecyldimethyl ammonium methocarbonate was produced.

[0074] Initially, the solution consisted of two phases. The top layerwas essentially pure didecylmethyl amine. After 15 hours, the solutionwas a single phase. When a sample of the solution after 15 hours ofheating was allowed to cool to room temperature, it became hazy andseparated into two phases.

[0075] According to gas chromatography, about 90 to 95% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after 15 hours of heating and about 99% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after 28 hours of heating.

EXAMPLE 2

[0076] The reactor was charged with didecylmethylamine, propylenecarbonate, and methanol at a molar ratio of 1:1.2:6.5. The mixture washeated to 130° C. for 16 hours. Didecyldimethyl ammonium methocarbonatewas produced. Initially, the solution consisted of two phases. Afterheating, the solution remained in two phases. The top layer was high intridecylamine.

[0077] According to gas chromatography, about 75-80% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after the 16 hours of heating.

EXAMPLE 3

[0078] A reactor was charged with didecylmethylamine, propylenecarbonate, and methanol at a molar ratio of 1:1.6:10. The mixture washeated to 130° C. for 20 hours. Didecyldimethyl ammonium methocarbonatewas produced. Initially, the solution consisted of two phases. After 16hours of heating, the solution consisted of one phase.

[0079] According to gas chromatography, about 85-90% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after the 20 hours of heating.

EXAMPLE 4

[0080] The reactor was charged with didecylmethylamine (100% pure),propylene carbonate, and methanol at a molar ratio of 1:2:10. Themixture was heated to 140° C. for 23 hours. Didecyldimethyl ammoniummethocarbonate was produced. Initially, the solution consisted of twophases. After 6 hours of heating, the solution consisted of one phase.

[0081] According to gas chromatography, about 97-100% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after the 23 hours of heating.

EXAMPLE 5

[0082] The reactor was charged with 233 g (0.75 moles)didecylmethylamine (96% (w/w) pure and 4% (w/w) tridecylamine), 76.5 g(0.75 moles) propylene carbonate, 67.5 g (0.75 moles) dimethylcarbonate, and 233 g (7.5 moles) methanol. The mixture was heated to140° C. for 8.5 hours. Didecyl-dimethyl ammonium methocarbonate wasproduced. Initially, the solution consisted of two phases. After 2.5hours, the solution consisted of one phase.

[0083] According to gas chromatography, about 75, 95, and 99% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after 2.5, 5.5, and 8.5 hours of heating.

EXAMPLE 6

[0084] The reactor was charged with didecylmethylamine, propylenecarbonate, methanol, and dimethyl carbonate at a molar ratio of1:1:4:0.4. The mixture was heated to 150° C. for 20 hours.Didecyldimethyl ammonium methocarbonate was produced. Initially, thesolution consisted of two phases. After the 20 hours of heating, thesolution consisted of two phases.

[0085] According to gas chromatography, about 75% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after the 20 hours of heating.

EXAMPLE 7

[0086] The reactor was charged with didecylmethylamine, propylenecarbonate, methanol, and dimethyl carbonate at a molar ratio of1:1:10:1. The mixture was heated to 130° C. for 21 hours.Didecyldimethyl ammonium methocarbonate was produced. Initially, thesolution consisted of two phases. After the 21 hours of heating, thesolution consisted of one phase.

[0087] According to gas chromatography, about 97% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after the 21 hours of heating.

EXAMPLE 8

[0088] The reactor was charged with didecylmethylamine, propylenecarbonate, methanol, and dimethyl carbonate at a molar ratio of1:1:7:0.7. The mixture was heated to 140° C. for 15 hours.Didecyldimethyl ammonium methocarbonate was produced. Initially, thesolution consisted of two phases. After 6 hours of heating, the solutionconsisted of one phase.

[0089] According to gas chromatography, about 98% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after the 15 hours of heating.

EXAMPLE 9

[0090] The reactor was charged with didecylmethylamine, propylenecarbonate, methanol, and dimethyl carbonate at a molar ratio of 1:1:4:1.The mixture was heated to 150° C. for 17 hours. Didecyldimethyl ammoniummethocarbonate was produced. Initially, the solution consisted of twophases. After the 17 hours of heating, the solution consisted of onephase.

[0091] According to gas chromatography, about 85% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after 17 hours of heating.

EXAMPLE 10

[0092] The reactor was charged with didecylmethylamine, propylenecarbonate, methanol, and dimethyl carbonate at a molar ratio of1:1:7:0.7. The mixture was heated to 150° C. for 16 hours.Didecyldimethyl ammonium methocarbonate was produced. Initially, thesolution consisted of two phases. After 3 hours of heating, the solutionconsisted of one phase.

[0093] According to gas chromatography, about 98% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after the 16 hours of heating.

EXAMPLE 11

[0094] The reactor was charged with didecylmethylamine, propylenecarbonate, methanol, and dimethyl carbonate at a molar ratio of1:1:10:1. The mixture was heated to 120° C. for 28 hours.Didecyldimethyl ammonium methocarbonate was produced. Initially, thesolution consisted of two phases. After 10 hours of heating, thesolution consisted of one phase.

[0095] According to gas chromatography, about 98-100% of thedidecylmethylamine was converted to didecyldimethyl ammoniummethocarbonate after the 28 hours of heating.

EXAMPLE 12

[0096] The reactor was charged with didecylmethylamine, propylenecarbonate, methanol, and dimethyl carbonate at a molar ratio of1:1:10:1. The mixture was heated to 140° C. for 15 hours.Didecyldimethyl ammonium methocarbonate was produced.

[0097] According to gas chromatography, 95-98% of the didecylmethylaminewas converted to didecyldimethyl ammonium methocarbonate after the 15hours of heating.

EXAMPLE 13

[0098] The reactor was charged with dodecyldimethylamine, propylenecarbonate, and methanol at a molar ratio of 1:2:10. The mixture washeated to 140° C. for 6 hours. Dodecyltrimethyl ammonium methocarbonatewas produced.

[0099] According to gas chromatography, 96% and 100% of thedodecyldimethylamine, respectively, was converted to dodecyltrimethylammonium methocarbonate after 3 and 6 hours of heating.

EXAMPLE 14

[0100] The reactor was charged with dodecyldimethylamine, propylenecarbonate, dimethyl carbonate, and methanol at a molar ratio of1:1:1:10. The mixture was heated to 140° C. for 3 hours.Dodecyltrimethyl ammonium methocarbonate was produced.

[0101] According to gas chromatography, 100% of the dodecyldimethylaminewas converted to dodecyltrimethyl ammonium methocarbonate after the 3hours of heating.

EXAMPLE 15

[0102] The reactor was charged with dioctylmethylamine, propylenecarbonate, and methanol at a molar ratio of 1:2:10. The mixture washeated to 140° C. for 14 hours. Dioctyldimethyl ammonium methocarbonatewas produced. Initially, the solution consisted of two phases. After 5.5hours of heating, the solution consisted of one phase.

[0103] According to gas chromatography, 85% and 98% of thedioctylmethylamine, respectively, was converted to dioctyldimethylammonium methocarbonate after 5.5 and 14 hours of heating.

EXAMPLE 16

[0104] The reactor was charged with octadecyldimethylamine, propylenecarbonate, and methanol at a molar ratio of 1:2:10. The mixture washeated to 140° C. for 5 hours. Octadecyltrimethyl ammoniummethocarbonate was produced.

[0105] According to gas chromatography, 97% of theoctadecyldimethylamine was converted to octadecyltrimethyl ammoniummethocarbonate after the 5 hours of heating.

EXAMPLE 17

[0106] The reactor was charged with dioctadecylmethylamine, propylenecarbonate, and methanol at a molar ratio of 1:2:10. The mixture washeated to 140° C. for 26 hours. Dioctadecyldimethyl ammoniummethocarbonate was produced.

[0107] According to gas chromatography, 80% of thedioctadecylmethylamine was converted to dioctadecyldimethyl ammoniummethocarbonate.

EXAMPLE 18

[0108] The reactor was charged with trioctylamine, propylene carbonate,and methanol at a molar ratio of 1:2:10. The mixture was heated to 140°C. for 38 hours. Trioctylmethyl ammonium methocarbonate was produced.Initially, the solution consisted of two phases. After 38 hours ofheating, the solution still consisted of two phase.

[0109] According to gas chromatography, 85% of the trioctylamine wasconverted to trioctylmethyl ammonium methocarbonate after the 38 hoursof heating.

EXAMPLE 19

[0110] The reactor was charged with didecylmethylamine, ethylenecarbonate, and methanol at a molar ratio of 1:2:10. The mixture washeated to 140° C. for 26 hours. Didecyldimethyl ammonium methocarbonatewas produced. Initially, the solution consisted of two phases. After 6hours of heating, the solution consisted of one phase. Furthermore,after 26 hours the solution was dark.

[0111] According to gas chromatography, 85% of the didecylmethylaminewas converted to didecyldimethyl ammonium methocarbonate after the 26hours of heating.

[0112] C. Preparation of Quaternary Ammonium Bicarbonate

EXAMPLE 20

[0113] The mixture from Example 1 was cooled and transferred to a roundbottom flask equipped with a Vigreux column having a distillation headcondenser receiving flask cooled in a dry ice acetone bath and aconnection to a vacuum system. The flask was placed in an oil bath andheated slowly as the vacuum was dropped to 0.2 atm. Distillationcontinued over a 3 hour period as the bath temperature was slowly raisedto 75° C. A total of 165 grams of liquid was collected. Using a densitycurve based on known mixtures of dimethyl carbonate (density 1.07 g/cc)and methanol (density 0.79 g/cc), it was estimated that the mixture fromExample 1 contained 20% by weight of dimethyl carbonate. 400 grams ofwater were added to the flask and the flask was placed in the oil bath.The vacuum was slowly applied to distill out water (about 250 gramstotal) at a temperature of 55-75° C. over a period of about 5 hoursuntil a sample of the distillate had a density of greater than 0.98g/cc. The product contained about 600 grams of combined quaternaryammonium bicarbonate and carbonate (60%), propylene glycol and water andless than 1% methanol. An additional 110 grams of water was added todilute the mixture to yield a product containing 50% by weight ofcombined quaternary ammonium bicarbonate and carbonate, 16% by weight ofpropylene glycol, and 34% by weight of water.

EXAMPLE 21

[0114] The methocarbonate in the mixture obtained in Example 7 wasconverted to the corresponding bicarbonate and carbonate by theprocedure described in Example 20. The resulting mixture contained 50%by weight of combined quaternary ammonium bicarbonate and carbonate, 10%by weight of propylene glycol, and 40% by weight of water.

EXAMPLE 22

[0115] A 50 gallon reactor, equipped with a stripping condenser and a 30gallon receiver, was charged with 116.4 lbs (0.374 lb moles) ofdidecylmethyl amine, 38.2 lbs (0.374 lb moles) of propylene crabonate,33.7 lbs (0.374 lb moles) of dimethyl carbonate, and 119.7 g (3.740 lbmoles) of methanol. The reactor was heated to and maintained at 140° C.for 6-9 hours. The reactor was maintained at 150 psig. After 6 hours at140° C., the reactor was sampled to determine the percentage ofquaternary ammonium compound and free amine in the reactor. The reactionmixture was periodically sampled until the ratio of quaternary ammoniumcompound to unreacted amine was greater than 97.5:2.5. The quaternaryammonium compound was identified by NMR as didecyldimethylammoniummethocarbonate.

[0116] Excess methanol and dimethyl carbonate was removed by atmosphericstripping at 100° C. until no more distillate was collected. The reactorwas cooled to 60° C. The content of the stripping condenser and receiverwas drained into a 55 gallon drum. Full glycol cooling was applied tothe stripping condenser and receiver and full vacuum (˜4 mm Hg) wasapplied to the reactor system to further strip off any remainingdimethylcarbonate and methanol. When no more distillate was collected,the reactor was vented with nitrogen to atmospheric pressure. Thecontent of the receiver was drained into the 55 gallon drum. A total of129 lbs of dimethylcarbonate and methanol was collected in the drum.

[0117] To the content of the reactor at 60° C. was added 109.6 lbs ofwater. The reactor was heated and maintained at 80° C. for 2-3 hours.The didecyldimethylammonium methocarbonate was hydrolyzed todidecyldimethylammonium bicarbonate/carbonate. Additional water wasadded so that the final concentration of the quaternary ammoniumcompound was about 50-52%, the propylene glycol was about 9-11%, andmethanol was less than 3.5%.

[0118] All patents, applications, articles, publications, and testmethods mentioned above are hereby incorporated by reference.

[0119] Many variations of the present invention will suggest themselvesto those skilled in the art in light of the above detailed description.Such obvious variations are within the full intended scope of theappended claims.

In the claims:
 1. A method of preparing a quaternary ammoniummethocarbonate having the formula

wherein R¹ and R² are independently C₁-C₃₀ alkyl and R³ is a C₈-C₃₀alkyl, the method comprising reacting (a) an amine having the formulaNR1R²R³; (b) (i) a cyclic carbonate having the formula

wherein R⁴ is hydrogen or C₁-C₄ alkyl and n is an integer from 1 to 10,(ii) an aliphatic polyester having the formula

wherein R⁵, R⁶, R⁷, and R⁸ are independently hydrogen or C₁-C₁₀ alkyland m is an integer from 1 to 1200, or (iii) a mixture thereof; and (c)methanol to form the methocarbonate.
 2. The method of claim 1, whereinR¹ and R² are independently C₁-C₂₀ alkyl and R³ is a C₈-C₂₀ alkyl. 3.The method of claim 1, wherein R¹ and R² are independently C₁-C₁₆ alkyland R³ is a C₈-C₁₆ alkyl.
 4. The method of claim 3, wherein R¹ ismethyl.
 5. The method of claim 1, wherein R² is C₁-C₂₀ alkyl.
 6. Themethod of claim 5, wherein R² is methyl.
 7. The method of claim 5,wherein R² is C₈-C₁₂ alkyl.
 8. The method of claim 7, wherein R² is C₁₀alkyl.
 9. The method of claim 1, wherein R³ is C₈-C₂₀ alkyl.
 10. Themethod of claim 9, wherein R³ is C₈-C₁₂ alkyl.
 11. The method of claim10, wherein R³ is C₁₀ alkyl.
 12. The method of claim 1, wherein R¹ ismethyl and R² and R³ are independently C₈-C₁₂ alkyl.
 13. The method ofclaim 12, wherein R² and R³ are C₁₀ alkyl.
 14. The method of claim 1,wherein R¹ and R² are methyl and R³ is C₈-C₂₀ alkyl.
 15. The method ofclaim 1, wherein the amine is selected from the group consisting ofdidecylmethylamine, dodecyldimethylamine, dioctylmethylamine,octadecyldimethylamine, dioctadecylmethylamine, trioctylamine, and anycombination of any of the foregoing.
 16. The method of claim 1, whereinR⁴ is hydrogen or methyl.
 17. The method of claim 16, wherein the cycliccarbonate is ethylene carbonate.
 18. The method of claim 16, wherein thecyclic carbonate is propylene carbonate.
 19. The method of claim 1,wherein R⁵, R⁶, R⁷, and R⁸ are independently hydrogen or C₁-C₄ alkyl.20. The method of claim 19, wherein R⁵, R⁶, R⁷, and R⁸ are independentlyhydrogen or methyl.
 21. The method of claim 1, wherein R⁵ is methyl andR⁶, R⁷, and R⁸ are hydrogen.
 22. The method of claim 1, wherein m rangesfrom 1 to
 100. 23. The method of claim 1, wherein the molar ratio ofamine to component (b) ranges from about 1:1 to about 1:10.
 24. Themethod of claim 23, wherein the molar ratio of amine to component (b)ranges from about 1:2 to about 1:3.
 25. The method of claim 1, whereinthe molar ratio of amine to methanol ranges from about 1:2 to about1:20.
 26. The method of claim 1, wherein the reaction step is performedat from about 120 to about 160° C.
 27. The method of claim 26, whereinthe reaction step is performed at from about 120 to about 150° C. 28.The method of claim 27, wherein the reaction step is performed at fromabout 120 to about 140° C.
 29. The method of claim 1, further comprisingthe step of recovering the dimethyl carbonate.
 30. The method of claim1, wherein the reaction step comprises reacting (a) the amine; (b) (i)the cyclic carbonate, (ii) the aliphatic polyester, or (iii) a mixturethereof; (c) methanol; and (d) dimethylcarbonate.
 31. The method ofclaim 30, wherein the molar ratio of amine to dimethylcarbonate rangesfrom about 2:1 to about 1:3.
 32. A method of preparing didecyldimethylammonium methocarbonate comprising reacting (a) didecylmethylamine; (b)a cyclic carbonate selected from the group consisting of ethylenecarbonate, propylene carbonate, and mixtures thereof; and (c) methanolto form didecyldimethyl ammonium methocarbonate.
 33. The method of claim32, wherein the reaction step comprises reacting (a) didecylmethylamine;(b) a cyclic carbonate selected from the group consisting of ethylenecarbonate, propylene carbonate, and mixtures thereof; (c) methanol; and(d) dimethylcarbonate.
 34. The method of claim 32, wherein the cycliccarbonate is propylene carbonate.
 35. A method of preparing a quaternaryammonium bicarbonate having the formula

wherein R¹, R², and R³ are independently C₁-C₃₀ alkyl, the methodcomprising (a) preparing a quaternary ammonium methocarbonate by themethod of claim 1; and (b) converting the quaternary ammoniummethocarbonate to the quaternary ammonium bicarbonate.
 36. A method ofpreparing didecyldimethyl ammonium bicarbonate comprising (a) reacting(i) didecylmethylamine, (ii) a cyclic carbonate selected from the groupconsisting of ethylene carbonate, propylene carbonate, and mixturesthereof, and (iii) methanol to form didecyldimethyl ammoniummethocarbonate; and (b) converting the didecyldimethyl ammoniummethocarbonate to didecyldimethyl ammonium bicarbonate.
 37. The methodof claim 36, wherein step (a) comprises reacting (i) didecylmethylamine,(ii) a cyclic carbonate selected from the group consisting of ethylenecarbonate, propylene carbonate, and mixtures thereof, (iii) methanol,and (iv) dimethylcarbonate to form didecyldimethyl ammoniummethocarbonate.
 38. A method of preparing a mixture of quaternaryammonium bicarbonate and quaternary ammonium carbonate wherein thequaternary ammonium cation has the formula N⁺(CH₃)R¹R²R³ and R¹, R², andR³ are independently C₁-C₃₀ alkyl, the method comprising (a) preparing aquaternary ammonium methocarbonate by the method of claim 1; and (b)converting the quaternary ammonium methocarbonate to a mixture ofquaternary ammonium bicarbonate and quaternary ammonium carbonate.
 39. Amethod of preparing a quaternary ammonium alkylcarbonate having theformula

wherein R¹ and R² are independently C₁-C₃₀ alkyl, R³ is a C₈-C₃₀ alkyl,and R⁹ is a C₁-C₁₀ alkyl, the method comprising reacting (a) an aminehaving the formula NR¹R²R³; (b) an ester having the formula

wherein R¹⁰ is a C₁-C₁₀ alkyl; and (c) methanol to form the quaternaryammonium alkylcarbonate.
 40. The method of claim 39, wherein R¹ ismethyl and R² and R³ are independently C₈-C₁₂ alkyl.
 41. The method ofclaim 39, wherein the amine is selected from the group consisting ofdidecylmethylamine, dodecyldimethylamine, dioctylmethylamine,octadecyldimethylamine, dioctadecylmethylamine, trioctylamine, and anycombination of any of the foregoing.
 42. The method of claim 39, whereinthe molar ratio of amine to ester ranges from about 1:1 to about 1:10.43. The method of claim 42, wherein the molar ratio of amine to esterranges from about 1:2 to about 1:3.
 44. The method of claim 39, whereinthe molar ratio of amine to methanol ranges from about 1:2 to about1:20.
 45. The method of claim 39, wherein the reaction step is performedat from about 120 to about 160° C.
 46. The method of claim 45, whereinthe reaction step is performed at from about 120 to about 150° C. 47.The method of claim 46, wherein the reaction step is performed at fromabout 120 to about 140° C.
 48. The method of claim 39, furthercomprising the step of recovering alkanol having the formula R⁹OH. 49.The method of claim 39, wherein the reaction step comprises reacting (a)the amine; (b) the ester; (c) methanol; and (d) alkyl methyl carbonatehaving the formula CH₃OC(O)OR⁹.
 50. A method of preparing a quaternaryammonium bicarbonate having the formula

wherein R¹, R², and R³ are independently C₁-C₃₀ alkyl, the methodcomprising (a) preparing a quaternary ammonium alkylcarbonate by themethod of claim 39; and (b) converting the quaternary ammoniumalkylcarbonate to the quaternary ammonium bicarbonate.
 51. A method ofpreparing a quaternary ammonium methocarbonate having the formula

wherein R¹ and R² are independently C₁-C₃₀ alkyl and R³ is a C₈-C₃₀alkyl, the method comprising reacting (a) an amine having the formulaNR¹R²R³; (b) (i) a cyclic carbonate having the formula

wherein R⁴ is hydrogen or C₁-C₄ alkyl and n is an integer from 1 to 10,(ii) a polycarbonate, (iii) a carbonate ester, or (iv) a mixturethereof; and (c) methanol to form the methocarbonate.
 52. The method ofclaim 51, wherein the carbonate ester has the formula

wherein R⁹ is —CH₃ and R¹⁰ is a C₁-C₁₀ alkyl.